<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://unpkg.com/vue@next"></script>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <div id="app">
  <div>
    <input type="text" v-model:value="counter" class="cin_item">
  </div>
  <div class="content">
    <div class="item" @click="counter += 0">0</div>
    <div class="item" @click="counter += 1">1</div>
    <div class="item" @click="counter += 2">2</div>
    <div class="item" @click="counter += 3">3</div>
    <div class="item" @click="counter += 4">4</div>
    <div class="item" @click="counter += 5">5</div>
    <div class="item" @click="counter += 6">6</div>
    <div class="item" @click="counter += 7">7</div>
    <div class="item" @click="counter += 8">8</div>
    <div class="item" @click="counter += 9">9</div>
  </div>
</div>
</body>
<script>
  const Counter ={
    data(){
      return{
        counter:0
      }
    }
  }
  Vue.createApp(Counter).mount('#app')
</script>
</html>